As planned, Microsoft has ended retail sales of Windows 8 as well as stopped offering some versions of its Windows 7 operating system to original equipment manufacturers (OEMs).

This means that retailers will no longer be able to order more copies of Windows 8, which went on sale just over two years ago on 26 October 2012, although it'll still come pre-installed on new PCs as the software giant will continue to offer it to hardware vendors such as HP, Dell, Lenovo, and more.

As for Windows 7, the Home Basic, Home Premium, and Ultimate editions of the OS have been withdrawn from sale to vendors, which means that these editions will no longer come pre-installed on new PCs. However, that might not happen any time soon, considering that manufacturers as well as retailers still have large stocks of Windows 7 PCs.

While the end of Windows 7 will definitely frustrate consumers, given the fact that it still maintains a 53 percent market share, enterprises can relax for now, as Microsoft will continue to supply Windows 7 Professional edition to OEMs. The Redmond-based company says that it will provide one year of notice prior to the end of sale date.

Another point worth noting is that enterprise customers can still downgrade to earlier versions of the OS they have licensed. "To use prior versions of Windows software on PCs installed with newer versions, it is possible for consumers to obtain a license for downgrade rights. These downgrade rights will vary depending on if the software was acquired via Volume Licensing, OEM, or FPP", Microsoft said.